A fluorescent-lamp-shaped LED lamp in which a plurality of light emitting diodes instead of a fluorescent light source are attached to a ready-made-fluorescent-lamp lighting appliance is disclosed as an example of a conventional LED lighting lamp (for reference, see Patent Document 1). A vehicle-mounted-signal lamp fitting which uses a plurality of light emitting diodes as a light source is also known (for reference, see Patent Document 2). Each of the fluorescent-lamp-shaped LED lamp and the vehicle-mounted-signal lamp fitting in such conventional art usually has a structure in which a plurality of light emitting diodes 93 are mounted on one board 94, as shown in FIG. 12. For the board 94, a glass-epoxy-resinous board is usually used. The board 94 has an upper surface with conductive patterns printed on it to form a lighting circuit. Each of the light emitting diodes 93 includes leads 93a and lead-insertion holes 94a which are provided in the board 94 for insertion of the leads 93a therein, and is mounted on the board 94 by fixing each lead to the board by solder 93b. 
However, in the conventional-fluorescent-lamp-shaped LED lamp and the conventional-vehicle-mounted-signal lamp fitting, because the plurality of light emitting diodes 93 are fixed one by one to the board 94 heating value increases for soldering the light emitting diodes. Heat generated by soldering is transmitted to the light emitting diodes through the leads 93a, and therefore, a possibility arises that the light emitting diodes 93 are thermally damaged; thus lowering reliability as a lighting lamp. Moreover, there is a problem that when the lighting lamp has high power, thermal capacity of the light emitting diodes is inevitably increased, and heat necessary for soldering the light emitting diodes is absorbed by the high-heat-capacity light emitting diodes, that makes it difficult to solder the diodes. Furthermore, because the light emitting diodes are fixed by soldering, there is a problem that removal of damaged light emitting diodes needs troublesome and time-consuming operations, and therefore, exchange of its whole fitting is needed, instead of just exchanging the light emitting diodes, resulting in cost increase.
Patent Document 1: Japanese Patent Application publication No. 2004-303614 (pages 5-7, FIGS. 1 and 2)
Patent Document 2: Japanese Patent Application publication No. 2000-222915 (page 2, FIGS. 5 and 6)